
Heat extracted from the evaporator (cold reservoir)
Q
C
¼ Q
41
¼ h
4
h
1
¼ h
4
h
2
¼ 1137 313:4 ¼ 823:6kJ=kg:
Hence, coefficient of performance of refrigerator, b ¼
h
4
h
1
h
3
h
4
¼
823:6
336:3
¼ 2:449:
Heat transferred from the condenser (hot reservoir)
Q
H
¼ Q
32
¼ h
2
h
3
¼ 313:4 1473:3 ¼1159:9kJ=kg
Hence, coefficient of performance of heat pump, b
0
¼
h
2
h
3
h
4
h
3
¼
1159:9
336:3
¼ 3:449:
Thus, both the coefficients of performance are greater than unity, and the coefficient of perfor-
mance of the heat pump is one greater than that of the refrigerator – even though the devices are not
reversible. If the devices had been reversible, i.e. had followed the reversed Carnot cycle, ...